Fair Value Measurements - Nonrecurring Fair Value Measures Within Level 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Impairment of Assets	$ 519,129	$ 0	$ 0
Fair Value, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Impairment of Assets	55,437	0	0
Pipeline and Storage | Fair Value, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Impairment of Assets	46,075	0	0
Fair Value	12,133
Exploration and Production
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Impairment of Assets	473,054
Exploration and Production | Fair Value, Nonrecurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Impairment of Assets	9,362	$ 0	$ 0
Property, plant, and equipment, fair value	$ 3,000